Efeitos da divulgação de notícias do desastre da Samarco em Mariana : um estudo de eventos na Vale e BHP

• Autor(a) principal: Barcellos, Sabrina Sobrinho
• Data de Publicação: 2018
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Espírito Santo (riUfes)
• Texto Completo: http://repositorio.ufes.br/handle/10/8877
• topic: Desenvolvimento Sustentável; Hipótese de Mercado Eficiente; Ciências Contábeis; Desastres ambientais - Mariana (MG).; 657

From the twentieth century, organizations started to worry about sustainable development, that is, to generate economic development without forgetting socio-environmental issues. This new paradigm does not exclude the need for wealth generation and return to shareholders. Given the complexity of the environmental relationship and performance in the stock markets, this research intends to study, in the context of the Mariana disaster involving Samarco, whether news released by Vale and BHP companies on November 2015 affected the return of companies. We used the event study methodology, derived from the Efficient- Market Hypothesis, to determine if the news disclosed by these companies in the period from November 5, 2015 to June 30, 2017 affected the return of the shares of the controlling companies of Samarco: Vale and BHP. Thus event windows were made to check the abnormal returns seven days before and after each news. Thus, of all the news released by the companies during the period of analysis, there were 26 news stories released by Vale and 13 by BHP. The results indicate that the market reacted statistically to 57.7% of the news published by Vale and 61% of the news reported by BHP. It was observed that among the significant news, those that indicated losses in processes or financial results below expectations, brought negative returns, while disclosures about agreements and release of resources to minimize the damages of the disaster, were directly related to abnormal positive returns. News related to Samarco's and its parent's attempts to mitigate damages were generally unrelated to abnormal returns. Further research may further study the disclosures about environmental information that most impact the abnormal return in the event of disasters.